Search results for: objective inequality
2845 Potential Use of Leaching Gravel as a Raw Material in the Preparation of Geo Polymeric Material as an Alternative to Conventional Cement Materials
Authors: Arturo Reyes Roman, Daniza Castillo Godoy, Francisca Balarezo Olivares, Francisco Arriagada Castro, Miguel Maulen Tapia
Abstract:
Mining waste–based geopolymers are a sustainable alternative to conventional cement materials due to their contribution to the valorization of mining wastes as well as to the new construction materials with reduced fingerprints. The objective of this study was to determine the potential of leaching gravel (LG) from hydrometallurgical copper processing to be used as a raw material in the manufacture of geopolymer. NaOH, Na2SiO3 (modulus 1.5), and LG were mixed and then wetted with an appropriate amount of tap water, then stirred until a homogenous paste was obtained. A liquid/solid ratio of 0.3 was used for preparing mixtures. The paste was then cast in cubic moulds of 50 mm for the determination of compressive strengths. The samples were left to dry for 24h at room temperature, then unmoulded before analysis after 28 days of curing time. The compressive test was conducted in a compression machine (15/300 kN). According to the laser diffraction spectroscopy (LDS) analysis, 90% of LG particles were below 500 μm. The X-ray diffraction (XRD) analysis identified crystalline phases of albite (30 %), Quartz (16%), Anorthite (16 %), and Phillipsite (14%). The X-ray fluorescence (XRF) determinations showed mainly 55% of SiO2, 13 % of Al2O3, and 9% of CaO. ICP (OES) concentrations of Fe, Ca, Cu, Al, As, V, Zn, Mo, and Ni were 49.545; 24.735; 6.172; 14.152, 239,5; 129,6; 41,1;15,1, and 13,1 mg kg-1, respectively. The geopolymer samples showed resistance ranging between 2 and 10 MPa. In comparison with the raw material composition, the amorphous percentage of materials in the geopolymer was 35 %, whereas the crystalline percentage of main mineral phases decreased. Further studies are needed to find the optimal combinations of materials to produce a more resistant and environmentally safe geopolymer. Particularly are necessary compressive resistance higher than 15 MPa are necessary to be used as construction unit such as bricks.Keywords: mining waste, geopolymer, construction material, alkaline activation
Procedia PDF Downloads 922844 Using Open Source Data and GIS Techniques to Overcome Data Deficiency and Accuracy Issues in the Construction and Validation of Transportation Network: Case of Kinshasa City
Authors: Christian Kapuku, Seung-Young Kho
Abstract:
An accurate representation of the transportation system serving the region is one of the important aspects of transportation modeling. Such representation often requires developing an abstract model of the system elements, which also requires important amount of data, surveys and time. However, in some cases such as in developing countries, data deficiencies, time and budget constraints do not always allow such accurate representation, leaving opportunities to assumptions that may negatively affect the quality of the analysis. With the emergence of Internet open source data especially in the mapping technologies as well as the advances in Geography Information System, opportunities to tackle these issues have raised. Therefore, the objective of this paper is to demonstrate such application through a practical case of the development of the transportation network for the city of Kinshasa. The GIS geo-referencing was used to construct the digitized map of Transportation Analysis Zones using available scanned images. Centroids were then dynamically placed at the center of activities using an activities density map. Next, the road network with its characteristics was built using OpenStreet data and other official road inventory data by intersecting their layers and cleaning up unnecessary links such as residential streets. The accuracy of the final network was then checked, comparing it with satellite images from Google and Bing. For the validation, the final network was exported into Emme3 to check for potential network coding issues. Results show a high accuracy between the built network and satellite images, which can mostly be attributed to the use of open source data.Keywords: geographic information system (GIS), network construction, transportation database, open source data
Procedia PDF Downloads 1622843 The Effect of 6 Weeks Endurance Swimming Training on Blood Glucose and Cardiac Tissue Antioxidants in Diabetic Rats
Authors: Kh. Dehkordi, R. Sharifi Gholam, S. Arshadi
Abstract:
Objective: Oxidative stress is produced under diabetic conditions and possibly causes various forms of tissue damage inpatients with diabetes. Antioxidants defend against the harmful effect of free radicals, which are associated with heart disease, cancer, arthritis, aging and many other diseases1). Antioxidants are very stable molecules capable of neutralizing free radicals by donating an electron to them.The aim of this study was to examine the effect of swimming training, fenugreek seed extract and glibenclamide on plasma glucose and cardiac antioxidants activity in diabetic rats. Design: For this purpose, fifty male wistar rats were divided into five groups, two groups of control rats (diabetic control [DC] and healthy control [HC]), one group of endurance swimming training (EST), one group of fenugreek seed extract highdose (F1, 1.74 g/kg b.w), one group of fenugreek seed extract middle dose (F2, 0.87 g/kg b.w), one group of glibenclamide (G, 0.5 mg/kg b.w). Materials and Methods: Diabetes induced by streptozotocine (STZ), data was analyzed using the one-way ANOVA followed by a Tukey test. Significance level was 0.05. Results: All of the groups' exception of HC showed significant decrease in body weight (P < 0.05), but the diabetic control and swimming training group exhibited a more decrease. All of the groups have shown a significant decrease in plasma glucose than DC group (P < 0.05) but this reduction was more in G group than DC no HC group. S, G and HC groups have shown significant increase in cardiac antioxidant than DC group (P < 0.05) but there wasn't significant difference in other groups (P > 0.05). Conclusion: The present results indicate that regular swimming training lead to decrease in plasma glucose and enhanced cardiac antioxidants in diabetic rats.Keywords: swimming, glucose, cardiac, antioxidants
Procedia PDF Downloads 2952842 Vision Zero for the Caribbean Using the Systemic Approach for Road Safety: A Case Study Analyzing Jamaican Road Crash Data (Ongoing)
Authors: Rachelle McFarlane
Abstract:
The Second Decade of Action Road Safety has begun with increased focus on countries who are disproportionately affected by road fatalities. Researchers highlight the low effectiveness of road safety campaigns in Latin America and the Caribbean (LAC) still reporting approximately 130,000 deaths and six million injuries annually. The regional fatality rate 19.2 per 100,000 with heightened concern for persons 15 to 44 years. In 2021, 483 Jamaicans died in 435 crashes, with 33% of these fatalities occurring during Covid-19 curfew hours. The study objective is to conduct a systemic safety review of Jamaican road crashes and provide a framework for its use in complementing traditional methods. The methodology involves the use of the FHWA Systemic Safety Project Selection Tool for analysis. This tool reviews systemwide data in order to identify risk factors across the network associated with severe and fatal crashes, rather that only hotspots. A total of 10,379 crashes with 745 fatalities and serious injuries were reviewed. Of the focus crash types listed, 50% of ‘Pedestrian Accidents’ resulted in fatalities and serious injuries, followed by 32% ‘Bicycle’, 24% ‘Single’ and 12% of ‘Head-on’. This study seeks to understand the associated risk factors with these priority crash types across the network and recommend cost-effective countermeasures across common sites. As we press towards Vision Zero, the inclusion of the systemic safety review method, complementing traditional methods, may create a wider impact in reducing road fatalities and serious injury by targeting issues across network with similarities; focus crash types and contributing factors.Keywords: systemic safety review, risk factors, road crashes, crash types
Procedia PDF Downloads 832841 Antepartum and Postpartum Pulmonary Cryptococcosis: A Case Report and Systematic Review
Authors: Ghadeer M Alkusayer, Adelicia Yu, Pamela Orr
Abstract:
Study objective: To report a case of postpartum pulmonary cryptococcal infection (CCI) in an otherwise healthy 35-year-old woman. Additionally, the cases of pulmonary cryptococcal infections either in the antepartum or the postpartum period with pregnancy outcomes, were systematically reviwed. Methods: A systematic search of Cochrane Library, MEDLINE, and EMBASE was conducted for peer-reviewed studies without date restrictions, published in English and relating to CCI during pregnancy or postpartum period. Conference press, editorials, opinion pieces and letters were excluded. Two authors independently screened citations and full-text articles, extracted data and assessed study quality. Given the heterogeneity of study designs, a narrative synthesis was conducted. Results: The search identified 128 references, of which 22 case reports and series met the inclusion criteria. This is a total of 29 women (including the current case) . The mean age of the women was 28.3 ± 12.3 years. Nine (31.03%) presented and were diagnosed in the postpartum period. Two (6.90%) of the patients were reported as immunocompromised with HIV. Four maternal deaths (13.79%) were found in this case series with one (4.3%) patient with severe neurological deficits. Four (17.4%) infant deaths were reported. Women primary presentation varied with chest pain 13 (44.82%), headache 10 (35.70%), dyspnea 19 (65.51%), or fever 12 (41.38%). Three studies reported placental pathology positive for C. neoformans. Conclusion: This case of pulmonary cryptococcal infection in the postpartum period is an important addition to the literature of this rare infection in pregnancy. The patient is not immunocompromised. The patient was successfully treated with 4 months of Fluconazole 400 mg and continued to breastfeed the healthy baby.Keywords: pulmonary cryptococcus, pregnancy, cryptococci , postpartum
Procedia PDF Downloads 1332840 Customer Churn Prediction by Using Four Machine Learning Algorithms Integrating Features Selection and Normalization in the Telecom Sector
Authors: Alanoud Moraya Aldalan, Abdulaziz Almaleh
Abstract:
A crucial component of maintaining a customer-oriented business as in the telecom industry is understanding the reasons and factors that lead to customer churn. Competition between telecom companies has greatly increased in recent years. It has become more important to understand customers’ needs in this strong market of telecom industries, especially for those who are looking to turn over their service providers. So, predictive churn is now a mandatory requirement for retaining those customers. Machine learning can be utilized to accomplish this. Churn Prediction has become a very important topic in terms of machine learning classification in the telecommunications industry. Understanding the factors of customer churn and how they behave is very important to building an effective churn prediction model. This paper aims to predict churn and identify factors of customers’ churn based on their past service usage history. Aiming at this objective, the study makes use of feature selection, normalization, and feature engineering. Then, this study compared the performance of four different machine learning algorithms on the Orange dataset: Logistic Regression, Random Forest, Decision Tree, and Gradient Boosting. Evaluation of the performance was conducted by using the F1 score and ROC-AUC. Comparing the results of this study with existing models has proven to produce better results. The results showed the Gradients Boosting with feature selection technique outperformed in this study by achieving a 99% F1-score and 99% AUC, and all other experiments achieved good results as well.Keywords: machine learning, gradient boosting, logistic regression, churn, random forest, decision tree, ROC, AUC, F1-score
Procedia PDF Downloads 1282839 The Television as an Affordable and Effective Way to Promote Healthy Diet and Physical Activity to Prevent or Treat Obesity
Authors: P. Gil Del Álamo, J. García Pereda, A. Castañeda De La Paz, D. Arazola Lopez, M. D. Cubiles De La Vega, A. Enguíx González, J. M. Muñoz Pichardo
Abstract:
In the last decades, obesity has more than doubled and is, with overweight, the second leading cause of preventable death. Despite multiple strategies against obesity, no country to date has reduced the number of obese people. To achieve World Health Organization’s target to reverse this tendency we need dramatic and different actions to engage the civil society in creating demand for a healthy style of life. The objective of this study is to demonstrate that a social media as the television can be used to convince the civil society that a healthy nutrition and physical activity are affordable, effective and necessary to prevent and to treat the obesity. Methodology: 61 individuals (34 women and 27 men) with obesity (mean BMI 45,51) were recruited to follow during 22 weeks an intensive lifestyle intervention in order to lose weight in a healthy manner. They were not isolated or moved from their usual environment. This program included endocrinological and nutritional assessment, promotion of physical activity and psychological support. BMI was measured every week. Time to leave obesity between men and women was analyzed with a survival analysis. Results: BMI decreased in all the cases. Analysing Time to leave obesity, around the week 30, 25% of men leave the obesity and around the week 39, 25% of women leave the obesity too. Conclusion: We demonstrate the audience that improving the quality of the diet and increasing the physical activity is a realistic way to lose weight. This evidence can encourage the people to act in their own self-interest changing their style of life in order to prevent or to reduce their overweight.Keywords: obesity epidemic, obesity prevention, obesity strategies, social media
Procedia PDF Downloads 2822838 Teenagers in Conflict with Law: Exploratory Study about Psychic Suffering
Authors: Carolina Alcântara, Ileno Costa
Abstract:
This study had the objective to systemize the main psycho-social and socioeducational aspects that related with the psychic suffering of adolescents in conflict of law and freedom privation. This research wanted to verify the signals and symptoms identified trough themselves perceptions related to their condition of health/insanity. In a similar way, it was objectified to know the opinions of the ambient conditions of the institution the use of the currently available resources for Health Service and Educational Service. The methodological proposal is based on the quant-qualitative analysis of interviews half-structuralized carried through with 36 teenagers was using psychiatric medication continuously. The data had pointed the experiences of sleeplessness and nightmares, associates or not with experiences of loss of reality (hallucinations) had constituted the illness most frequent. The self-punishment behavior appeared at second place. With regard to the ambient factors, it was verified that institution had, in general way, guaranteed the physical integrity and the maintenance of the health. Amongst the current available resources of Health Service, the administration of anticonvulsivants, in association with other psychotropic drugs has been widely used. The school was viewed as important device of available in the institution. By means of the adolescent’s understanding who do not like to go to the school, they don’t disqualify the knowledge, in contrast, they wanted for knowledge, however, they were frustrated for not having their educational supplies adequately, affirming that the school is weak or they do not learn. Finally, among the possible conclusions guided for the Winnicott’s thought, it was observed that institution in analysis is a representative of the paternal function. However, to begin the self-cure process is necessary that formation of therapeutical bonds. The group of teachers is identified as the main tool of change.Keywords: serious psychic suffering, adolescent in conflict with the law, delinquency, privation of freedom
Procedia PDF Downloads 2332837 Statistical Model of Water Quality in Estero El Macho, Machala-El Oro
Authors: Rafael Zhindon Almeida
Abstract:
Surface water quality is an important concern for the evaluation and prediction of water quality conditions. The objective of this study is to develop a statistical model that can accurately predict the water quality of the El Macho estuary in the city of Machala, El Oro province. The methodology employed in this study is of a basic type that involves a thorough search for theoretical foundations to improve the understanding of statistical modeling for water quality analysis. The research design is correlational, using a multivariate statistical model involving multiple linear regression and principal component analysis. The results indicate that water quality parameters such as fecal coliforms, biochemical oxygen demand, chemical oxygen demand, iron and dissolved oxygen exceed the allowable limits. The water of the El Macho estuary is determined to be below the required water quality criteria. The multiple linear regression model, based on chemical oxygen demand and total dissolved solids, explains 99.9% of the variance of the dependent variable. In addition, principal component analysis shows that the model has an explanatory power of 86.242%. The study successfully developed a statistical model to evaluate the water quality of the El Macho estuary. The estuary did not meet the water quality criteria, with several parameters exceeding the allowable limits. The multiple linear regression model and principal component analysis provide valuable information on the relationship between the various water quality parameters. The findings of the study emphasize the need for immediate action to improve the water quality of the El Macho estuary to ensure the preservation and protection of this valuable natural resource.Keywords: statistical modeling, water quality, multiple linear regression, principal components, statistical models
Procedia PDF Downloads 832836 Determination of the Thermophysical Characteristics of the Composite Material Clay Cement Paper
Authors: A. Ouargui, N. Belouaggadia, M. Ezzine
Abstract:
In Morocco, the building sector is largely responsible for the evolution of energy consumption. The control of energy in this sector remains a major issue despite the rise of renewable energies. The design of an environmentally friendly building requires mastery and knowledge of energy and bioclimatic aspects. This implies taking into consideration of all the elements making up the building and the way in which energy exchanges take place between these elements. In this context, thermal insulation seems to be an ideal starting point for reducing energy consumption and greenhouse gas emissions. In this context, thermal insulation seems to be an ideal starting point for reducing energy consumption and greenhouse gas emissions. The aim of this work is to provide some solutions to reduce energy consumption while maintaining thermal comfort in the building. The objective of our work is to present an experimental study on the characterization of local materials used in the thermal insulation of buildings. These are paper recycling stabilized with cement and clay. The thermal conductivity of these materials, which were constituted based on sand, clay, cement; water, as well as treated paper, was determined by the guarded-hot-plate method. It involves the design of two materials that will subsequently be subjected to thermal and mechanical tests to determine their thermophysical properties. The results show that the thermal conductivity decreases as well in the case of the paper-cement mixture as that of the paper-clay and seems to stabilize around 40%. Measurements of mechanical properties such as flexural strength have shown that the enrichment of the studied material with paper makes it possible to reduce the flexural strength by 20% while optimizing the conductivity.Keywords: building, composite material, insulation, thermal conductivity, paper residue
Procedia PDF Downloads 1212835 Application of the Urban Forest Credit Standard as a Tool for Compensating CO2 Emissions in the Metalworking Industry: A Case Study in Brazil
Authors: Marie Madeleine Sarzi Inacio, Ligiane Carolina Leite Dauzacker, Rodrigo Henriques Lopes Da Silva
Abstract:
The climate changes resulting from human activity have increased interest in more sustainable production practices to reduce and offset pollutant emissions. Brazil, with its vast areas capable of carbon absorption, holds a significant advantage in this context. However, to optimize the country's sustainable potential, it is important to establish a robust carbon market with clear rules for the eligibility and validation of projects aimed at reducing and offsetting Greenhouse Gas (GHG) emissions. In this study, our objective is to conduct a feasibility analysis through a case study to evaluate the implementation of an urban forest credits standard in Brazil, using the Urban Forest Credits (UFC) model implemented in the United States as a reference. Thus, the city of Ribeirão Preto, located in Brazil, was selected to assess the availability of green areas. With the CO2 emissions value from the metalworking industry, it was possible to analyze information in the case study, considering the activity. The QGIS software was used to map potential urban forest areas, which can connect to various types of geospatial databases. Although the chosen municipality has little vegetative coverage, the mapping identified at least eight areas that fit the standard definitions within the delimited urban perimeter. The outlook was positive, and the implementation of projects like Urban Forest Credits (UFC) adapted to the Brazilian reality has great potential to benefit the country in the carbon market and contribute to achieving its Greenhouse Gas (GHG) emission reduction goals.Keywords: carbon neutrality, metalworking industry, carbon credits, urban forestry credits
Procedia PDF Downloads 692834 Optimal Continuous Scheduled Time for a Cumulative Damage System with Age-Dependent Imperfect Maintenance
Authors: Chin-Chih Chang
Abstract:
Many manufacturing systems suffer failures due to complex degradation processes and various environment conditions such as random shocks. Consider an operating system is subject to random shocks and works at random times for successive jobs. When successive jobs often result in production losses and performance deterioration, it would be better to do maintenance or replacement at a planned time. A preventive replacement (PR) policy is presented to replace the system before a failure occurs at a continuous time T. In such a policy, the failure characteristics of the system are designed as follows. Each job would cause a random amount of additive damage to the system, and the system fails when the cumulative damage has exceeded a failure threshold. Suppose that the deteriorating system suffers one of the two types of shocks with age-dependent probabilities: type-I (minor) shock is rectified by a minimal repair, or type-II (catastrophic) shock causes the system to fail. A corrective replacement (CR) is performed immediately when the system fails. In summary, a generalized maintenance model to scheduling replacement plan for an operating system is presented below. PR is carried out at time T, whereas CR is carried out when any type-II shock occurs and the total damage exceeded a failure level. The main objective is to determine the optimal continuous schedule time of preventive replacement through minimizing the mean cost rate function. The existence and uniqueness of optimal replacement policy are derived analytically. It can be seen that the present model is a generalization of the previous models, and the policy with preventive replacement outperforms the one without preventive replacement.Keywords: preventive replacement, working time, cumulative damage model, minimal repair, imperfect maintenance, optimization
Procedia PDF Downloads 3532833 Attitude of Staff Nurses on Nursing Research and Its Utilization
Authors: Y. N. Shashidhara, B. S. Shakuntala
Abstract:
Introduction: Nursing practice is undergoing tremendous changes and challenges. In order to meet social challenges and needs, nursing practice must be research based. Research is needed to evaluate the effectiveness of nursing treatment modalities, to determine the impact of nursing care on the health of the patients or to test the theory of nursing practice. Objective of the study to explore the attitude of staff nurses on Nursing research and its utilization Methodology: The descriptive study design was adopted and 300 staff nurses were selected by systematic random sampling technique from eight hospitals. The attitude on nursing research was assessed by validated and reliable self-administered attitude scale which consists of 40 items. Results: The overall attitude mean score 130.2 (SD 11.5) regarding attitude on Nursing research and its utilization. Some of the findings are the majority of staff nurses (51% agreed and 18.3% strongly agreed) that they have all the motivation to use research findings if they get support. Nearly 25.3 percent of staff nurses agreed and 10.7 percent strongly agreed that they do not have time to conduct research. The majority of staff nurses 53.7 percent agreed that research will help in updating Nursing profession. Nearly 32.6 percent of staff nurses agreed and 20.5 percent strongly agreed that being able to use will make them better nurses. About 45.3 percent and 17.3 percent agreed and strongly agreed that knowledge gained through experience is more useful than research. Most (40%) of nurses agreed that thy do not have the authority to change the patient care practice. The majority of staff nurses (45.7 percent agreed and 13 percent strongly agreed) feel the research will consume their personal time. Majority, 50 percent of staff nurses agreed and 16.7 percent strongly agreed that to conduct and utilize research findings requires financial support. Majority 50 percent of staff nurses agreed and 12 percent strongly agreed that physicians will cooperate and value nursing research findings. Majority 67.3 percent of staff nurses had moderate positive and 32.7 percent of staff nurses had highly positive attitude towards Nursing research and its utilization. Conclusion: With this study we understanding that, the staff nurses have positive attitude regarding nursing research. If the nurses are supported and motivated for research utilization we can improve the patient care.Keywords: nurses, attitude, nursing research, research utilization
Procedia PDF Downloads 2472832 Growth Performance, Survival Rate and Feed Efficacy of Climbing Perch, Anabas testudineus, Feed Experimental Diet with Several Dosages of Papain Enzyme
Authors: Zainal A. Muchlisin, Muhammad Iqbal, Abdullah A. Muhammadar
Abstract:
The objective of the present study was to determine the optimum dose of papain enzyme in the diet for growing, survival rate and feed efficacy of climbing perch (Anabas testudineus). The study was conducted at the Laboratory of Aquatic of Faculty of Veterinary, Syiah Kuala University from January to March 2016. The completely randomized design was used in this study. Six dosages level of papain enzyme were tested with 4 replications i.e. 0 g kg-1 of feed, 20.0 g kg-1 feed, 22.5 g kg-1 of feed, 25.0 g kg-1 of feed, 27.5 g kg-1 of feed, and 30.0 g kg-1 of feed. The experimental fish fed twice a day at feeding level of 5% for 60 days. The results showed that weight gain ranged from 2.41g to 7.37g, total length gain ranged from 0.67cm to 3.17cm, specific growth rate ranged from 1.46 % day to 3.41% day, daily growth rate ranged from 0.04 g day to 0.13 g day, feed conversion ratio ranged from 1.94 to 3.59, feed efficiency ranged from 27.99% to 51.37%, protein retention ranged from 3.38% to 28.28%, protein digestibility ranged from 50.63% to 90.38%, and survival rate ranged from 88.89% to 100%. The highest rate for all parameters was found in the dosage of 3.00% papain enzyme kg feed. The ANOVA test showed that enzyme papain gave a significant effect on the weight gain, total length gain, daily growth rate, specific growth rate, feed conversion ratio, feed efficiency, protein retention, protein digestibility, and survival rate of the climbing perch (Anabas testudieus). The best enzyme papain dosage was 3.0%.Keywords: betok, feed conversion ratio, freshwater fish, nutrition, feeding
Procedia PDF Downloads 2302831 Atom Probe Study of Early Stage of Precipitation on Binary Al-Li, Al-Cu Alloys and Ternary Al-Li-Cu Alloys
Authors: Muna Khushaim
Abstract:
Aluminum-based alloys play a key role in modern engineering, especially in the aerospace industry. Introduction of solute atoms such as Li and Cu is the main approach to improve the strength in age-hardenable Al alloys via the precipitation hardening phenomenon. Knowledge of the decomposition process of the microstructure during the precipitation reaction is particularly important for future technical developments. The objective of this study is to investigate the nano-scale chemical composition in the Al-Cu, Al-Li and Al-Li-Cu during the early stage of the precipitation sequence and to describe whether this compositional difference correlates with variations in the observed precipitation kinetics. Comparing the random binomial frequency distribution and the experimental frequency distribution of concentrations in atom probe tomography data was used to investigate the early stage of decomposition in the different binary and ternary alloys which were experienced different heat treatments. The results show that an Al-1.7 at.% Cu alloy requires a long ageing time of approximately 8 h at 160 °C to allow the diffusion of Cu atoms into Al matrix. For the Al-8.2 at.% Li alloy, a combination of both the natural ageing condition (48 h at room temperature) and a short artificial ageing condition (5 min at 160 °C) induces increasing on the number density of the Li clusters and hence increase number of precipitated δ' particles. Applying this combination of natural ageing and short artificial ageing conditions onto the ternary Al-4 at.% Li-1.7 at.% Cu alloy induces the formation of a Cu-rich phase. Increasing the Li content in the ternary alloy up to 8 at.% and increasing the ageing time to 30 min resulted in the precipitation processes ending with δ' particles. Thus, the results contribute to the understanding of Al-alloy design.Keywords: aluminum alloy, atom probe tomography, early stage, decomposition
Procedia PDF Downloads 3342830 Elasticity Model for Easing Peak Hour Demand for Metrorail Transport System
Authors: P. K. Sarkar, Amit Kumar Jain
Abstract:
The demand for Urban transportation is characterised by a large scale temporal and spatial variations which causes heavy congestion inside metro trains in peak hours near Centre Business District (CBD) of the city. The conventional approach to address peak hour congestion, metro trains has been to increase the supply by way of introduction of more trains, increasing the length of the trains, optimising the time table to increase the capacity of the system. However, there is a limitation of supply side measures determined by the design capacity of the systems beyond which any addition in the capacity requires huge capital investments. The demand side interventions are essentially required to actually spread the demand across the time and space. In this study, an attempt has been made to identify the potential Transport Demand Management tools applicable to Urban Rail Transportation systems with a special focus on differential pricing. A conceptual price elasticity model has been developed to analyse the effect of various combinations of peak and nonpeak hoursfares on demands. The elasticity values for peak hour, nonpeak hour and cross elasticity have been assumed from the relevant literature available in the field. The conceptual price elasticity model so developed is based on assumptions which need to be validated with actual values of elasticities for different segments of passengers. Once validated, the model can be used to determine the peak and nonpeak hour fares with an objective to increase overall ridership, revenue, demand levelling and optimal utilisation of assets.Keywords: urban transport, differential fares, congestion, transport demand management, elasticity
Procedia PDF Downloads 3052829 Effects of Spent Dyebath Recycling on Pollution and Cost of Production in a Cotton Textile Industry
Authors: Dinesh Kumar Sharma, Sanjay Sharma
Abstract:
Textile manufacturing industry uses a substantial amount of chemicals not only in the production processes but also in manufacturing the raw materials. Dyes are the most significant raw material which provides colour to the fabric and yarn. Dyes are produced by using a large amount of chemicals both organic and inorganic in nature. Dyes are further classified as Reactive or Vat Dyes which are mostly used in cotton textiles. In the process of application of dyes to the cotton fiber, yarn or fabric, several auxiliary chemicals are also used in the solution called dyebath to improve the absorption of dyes. There is a very little absorption of dyes and auxiliary chemicals and a residual amount of all these substances is released as the spent dye bath effluent. Because of the wide variety of chemicals used in cotton textile dyes, there is always a risk of harmful effects which may not be apparent immediately but may have an irreversible impact in the long term. Colour imparted by the dyes to the water also has an adverse effect on its public acceptability and the potability. This study has been conducted with an objective to assess the feasibility of reuse of the spent dye bath. Studies have been conducted in two independent industries manufacturing dyed cotton yarn and dyed cotton fabric respectively. These have been referred as Unit-I and Unit-II. The studies included assessment of reduction in pollution levels and the economic benefits of such reuse. The study conclusively establishes that the reuse of spent dyebath results in prevention of pollution, reduction in pollution loads and cost of effluent treatment & production. This pollution prevention technique presents a good preposition for pollution prevention in cotton textile industry.Keywords: dyes, dyebath, reuse, toxic, pollution, costs
Procedia PDF Downloads 3852828 Effect of Cryogenic Treatment on Hybrid Natural Fiber Reinforced Polymer Composites
Authors: B. Vinod, L. J. Sudev
Abstract:
Natural fibers as reinforcement in polymer matrix material are gaining lot of attention in recent years. Natural fibers like jute, sisal, coir, hemp, banana etc. have attracted substantial importance as a potential structural material because of its attractive features along with its good mechanical properties. Cryogenic applications of natural fiber reinforced polymer composites are gaining importance. These materials need to possess good mechanical and physical properties at cryogenic temperatures to meet the high requirements by the cryogenic engineering applications. The objective of this work is to investigate the mechanical behavior of hybrid hemp/jute fibers reinforced epoxy composite material at liquid nitrogen temperature. Hybrid hemp/jute fibers reinforced polymer composite is prepared by hand lay-up method and test specimens are cut according to ASTM standards. These test specimens are dipped in liquid nitrogen for different time durations. The tensile properties, flexural properties and impact strength of the specimen are tested immediately after the specimens are removed from liquid nitrogen container. The experimental results indicate that the cryogenic treatment of the polymer composite has a significant effect on the mechanical properties of this material. The tensile properties and flexural properties of the hybrid hemp/jute fibers epoxy composite at liquid nitrogen temperature is higher than at room temperature. The impact strength of the material decreased after subjecting it to liquid nitrogen temperature.Keywords: liquid nitrogen temperature, polymer composite, tensile properties, flexural properties
Procedia PDF Downloads 3932827 Development of a Geomechanical Risk Assessment Model for Underground Openings
Authors: Ali Mortazavi
Abstract:
The main objective of this research project is to delve into a multitude of geomechanical risks associated with various mining methods employed within the underground mining industry. Controlling geotechnical design parameters and operational factors affecting the selection of suitable mining techniques for a given underground mining condition will be considered from a risk assessment point of view. Important geomechanical challenges will be investigated as appropriate and relevant to the commonly used underground mining methods. Given the complicated nature of rock mass in-situ and complicated boundary conditions and operational complexities associated with various underground mining methods, the selection of a safe and economic mining operation is of paramount significance. Rock failure at varying scales within the underground mining openings is always a threat to mining operations and causes human and capital losses worldwide. Geotechnical design is a major design component of all underground mines and basically dominates the safety of an underground mine. With regard to uncertainties that exist in rock characterization prior to mine development, there are always risks associated with inappropriate design as a function of mining conditions and the selected mining method. Uncertainty often results from the inherent variability of rock masse, which in turn is a function of both geological materials and rock mass in-situ conditions. The focus of this research is on developing a methodology which enables a geomechanical risk assessment of given underground mining conditions. The outcome of this research is a geotechnical risk analysis algorithm, which can be used as an aid in selecting the appropriate mining method as a function of mine design parameters (e.g., rock in-situ properties, design method, governing boundary conditions such as in-situ stress and groundwater, etc.).Keywords: geomechanical risk assessment, rock mechanics, underground mining, rock engineering
Procedia PDF Downloads 1392826 The Effect of the Epstein-Barr Virus on the Development of Multiple Sclerosis
Authors: Sina Mahdavi
Abstract:
Background and Objective: Multiple sclerosis (MS) is the most common inflammatory autoimmune disease of the central nervous system (CNS) that affects the myelination process in the CNS. Complex interactions of various "environmental or infectious" factors may act as triggers in autoimmunity and disease progression. The association between viral infections, especially Epstein-Barr virus (EBV) and MS, is one potential cause that is not well understood. In this study, we aim to summarize the available data on EBV infection in MS disease progression. Materials and Methods: For this study, the keywords "Multiple sclerosis," "Epstein-Barr virus," and "central nervous system" in the databases PubMed, Google Scholar, Sid, and MagIran between 2016 and 2022 were searched, and 14 articles were chosen, studied, and analyzed. Results: Demyelinated lesions isolated from MS patients contain EBNAs from EBV proteins. The EBNA1 domain contains a pentapeptide fragment identical to B-crystallin, a heat shock peptide, that is increased in peripheral B cells in response to B-crystallin infection, resulting in myelin-directed autoimmunity mediated by proinflammatory T cells. EBNA2, which is involved in the regulation of viral transcription, may enhance transcription from MS risk loci. A 7-fold increase in the risk of MS has been observed in EBV infection with HLA-DR15 synergy. Conclusion: EBV infection along with a variety of specific genetic risk alleles, cause inflammatory cascades in the CNS by infected B cells. There is a high expression of EBV during the course of MS, which indicates the relationship between EBV and MS, that this virus can play a role in the development of MS by creating an inflammatory state. Therefore, measures to modulate the expression of EBV may be effective in reducing inflammatory processes in demyelinated areas of MS patients.Keywords: multiple sclerosis, Epstein-Barr virus, central nervous system, EBNAs
Procedia PDF Downloads 862825 Modifying the Electrical Properties of Liquid Crystal Cells by Including TiO₂ Nanoparticles on a Substrate
Authors: V. Marzal, J. C. Torres, B. Garcia-Camara, Manuel Cano-Garcia, Xabier Quintana, I. Perez Garcilopez, J. M. Sanchez-Pena
Abstract:
At the present time, the use of nanostructures in complex media, like liquid crystals, is widely extended to manipulate their properties, either electrical or optical. In addition, these media can also be used to control the optical properties of the nanoparticles, for instance when they are resonant. In this work, the change on electrical properties of a liquid crystal cell by adding TiO₂ nanoparticles on one of the alignment layers has been analyzed. These nanoparticles, with a diameter of 100 nm and spherical shape, were deposited in one of the substrates (ITO + polyimide) by spin-coating in order to produce a homogeneous layer. These substrates were checked using an optical microscope (objective x100) to avoid potential agglomerates. The liquid crystal cell is then fabricated, using one of these substrates and another without nanoparticles, and filled with E7. The study of the electrical response was done through impedance measurements in a long range of frequencies (3 Hz- 6 MHz) and at ambient temperature. Different nanoparticle concentrations were considered, as well as pure E7 and an empty cell for comparison purposes. Results about the effective dielectric permittivity and conductivity are presented along with models of equivalent electric circuits and its physical interpretation. As a summary, it has been observed the clear influence of the presence of the nanoparticles, strongly modifying the electric response of the device. In particular, a variation of both the effective permittivity and the conductivity of the device have been observed. This result requires a deep analysis of the effect of these nanoparticles on the trapping of free ions in the device, allowing a controlled manipulation and frequency tuning of the electrical response of these devices.Keywords: alignment layer, electrical behavior, liquid crystal, TiO₂ nanoparticles
Procedia PDF Downloads 2032824 Determination of Identification and Antibiotic Resistance Rates of Pseudomonas aeruginosa Strains from Various Clinical Specimens in a University Hospital for Two Years, 2013-2015
Authors: Recep Kesli, Gulsah Asik, Cengiz Demir, Onur Turkyilmaz
Abstract:
Objective: Pseudomonas aeruginosa (P. aeruginosa) is an important nosocomial pathogen which causes serious hospital infections and is resistant to many commonly used antibiotics. P. aeruginosa can develop resistance during therapy and also it is very resistant to disinfectant chemicals. It may be found in respiratory support devices in hospitals. In this study, the antibiotic resistance of P. aeruginosa strains isolated from bronchial aspiration samples was evaluated retrospectively. Methods: Between October 2013 and September 2015, a total of 318 P. aeruginosa were isolated from clinical samples obtained from various intensive care units and inpatient patients hospitalized at Afyon Kocatepe University, ANS Practice and Research Hospital. Isolated bacteria identified by using both the conventional methods and automated identification system-VITEK 2 (bioMerieux, Marcy l’etoile France). Antibacterial resistance tests were performed by using Kirby-Bauer disc (Oxoid, Hampshire, England) diffusion method following the recommendations of CLSI. Results: Antibiotic resistance rates of identified 318 P. aeruginosa strains were found as follows for tested antibiotics; 32 % amikacin, 42% gentamicin, 43% imipenem, 43% meropenem, 50% ciprofloxacin, 57% levofloxacin, 38% cefepime, 63% ceftazidime, and 85% piperacillin/tazobactam. Conclusion: Resistance profiles change according to years and provinces for P. aeruginosa, so these findings should be considered empirical treatment choices. In this study, the highest and lowest resistance rates found against piperacillin/tazobactam % 85, and amikacin %32.Keywords: Pseudomonas aeruginosa, antibiotic resistance rates, intensive care unit, Pseudomonas spp.
Procedia PDF Downloads 2862823 To Design an Architectural Model for On-Shore Oil Monitoring Using Wireless Sensor Network System
Authors: Saurabh Shukla, G. N. Pandey
Abstract:
In recent times, oil exploration and monitoring in on-shore areas have gained much importance considering the fact that in India the oil import is 62 percent of the total imports. Thus, architectural model like wireless sensor network to monitor on-shore deep sea oil well is being developed to get better estimate of the oil prospects. The problem we are facing nowadays that we have very few restricted areas of oil left today. Countries like India don’t have much large areas and resources for oil and this problem with most of the countries that’s why it has become a major problem when we are talking about oil exploration in on-shore areas also the increase of oil prices has further ignited the problem. For this the use of wireless network system having relative simplicity, smallness in size and affordable cost of wireless sensor nodes permit heavy deployment in on-shore places for monitoring oil wells. Deployment of wireless sensor network in large areas will surely reduce the cost it will be very much cost effective. The objective of this system is to send real time information of oil monitoring to the regulatory and welfare authorities so that suitable action could be taken. This system architecture is composed of sensor network, processing/transmission unit and a server. This wireless sensor network system could remotely monitor the real time data of oil exploration and monitoring condition in the identified areas. For wireless sensor networks, the systems are wireless, have scarce power, are real-time, utilize sensors and actuators as interfaces, have dynamically changing sets of resources, aggregate behaviour is important and location is critical. In this system a communication is done between the server and remotely placed sensors. The server gives the real time oil exploration and monitoring conditions to the welfare authorities.Keywords: sensor, wireless sensor network, oil, sensor, on-shore level
Procedia PDF Downloads 4422822 Planning for Sustainability in the Built Environment
Authors: Adedayo Jeremiah Adeyekun, Samuel Oluwagbemiga Ishola
Abstract:
This paper aimed to identify the significance of sustainability in the built environment, the economic and environmental importance to building and construction projects. Sustainability in the built environment has been a key objective of research over the past several decades. Sustainability in the built environment requires reconciliation between economic, environmental and social impacts of design and planning decisions made during the life cycle of a project from inception to termination. Planning for sustainability in the built environment needs us to go beyond our individual disciplines to consider the variety of economic, social and environmental impacts of our decisions in the long term. A decision to build a green residential development in an isolated location may pass some of the test of sustainability through its reduction in stormwater runoff, energy efficiency, and ecological sustainability in the building, but it may fail to be sustainable from a transportation perspective. Sustainability is important to the planning, design, construction, and preservation of the built environment; because it helps these activities reflect multiple values and considerations. In fact, the arts and sciences of the built environment have traditionally integrated values and fostered creative expression, capabilities that can and should lead the sustainability movement as society seeks ways to live in dynamic balance with its own diverse needs and the natural world. This research aimed to capture the state-of-the-art in the development of innovative sustainable design and planning strategies for building and construction projects. Therefore, there is a need for a holistic selection and implication approach for identifying potential sustainable strategies applicable to a particular project and evaluating the overall life cycle impact of each alternative by accounting for different applicable impacts and making the final selection among various viable alternatives.Keywords: sustainability, built environment, planning, design, construction
Procedia PDF Downloads 1682821 Experimental Investigation of Mechanical Friction Influence in Semi-Hydraulic Clutch Actuation System Over Mileage
Authors: Abdul Azarrudin M. A., Pothiraj K., Kandasamy Satish
Abstract:
In the current automobile scenario, there comes a demand on more sophistication and comfort drive feel on passenger segments. The clutch pedal effort is one such customer touch feels in manual transmission vehicles, where the driver continuous to operate the clutch pedal in his entire the driving maneuvers. Hence optimum pedal efforts at green condition and over mileage to be ensured for fatigue free the driving. As friction is one the predominant factor and its tendency to challenge the technicality by causing the function degradation. One such semi-hydraulic systems shows load efficiency of about 70-75% over lifetime only due to the increase in friction which leads to the increase in pedal effort and cause fatigue to the vehicle driver. This work deals with the study of friction with different interfaces and its influence in the fulcrum points over mileage, with the objective of understanding the trend over mileage and determining the alternative ways of resolving it. In that one way of methodology is the reduction of friction by experimental investigation of various friction reduction interfaces like metal-to-metal interface and it has been tried out and is detailed further. Also, the specific attention has been put up considering the fulcrum load and its contact interfaces to move on with this study. The main results of the experimental data with the influence of three different contact interfaces are being presented with an ultimate intention of ending up into less fatigue with longer consistent pedal effort, thus smoothens the operation of the end user. The Experimental validation also has been done through rig-level test setup to depict the performance at static condition and in-parallel vehicle level test has also been performed to record the additional influences if any.Keywords: automobile, clutch, friction, fork
Procedia PDF Downloads 1142820 Computational Investigation of Secondary Flow Losses in Linear Turbine Cascade by Modified Leading Edge Fence
Authors: K. N. Kiran, S. Anish
Abstract:
It is well known that secondary flow loses account about one third of the total loss in any axial turbine. Modern gas turbine height is smaller and have longer chord length, which might lead to increase in secondary flow. In order to improve the efficiency of the turbine, it is important to understand the behavior of secondary flow and device mechanisms to curtail these losses. The objective of the present work is to understand the effect of a stream wise end-wall fence on the aerodynamics of a linear turbine cascade. The study is carried out computationally by using commercial software ANSYS CFX. The effect of end-wall on the flow field are calculated based on RANS simulation by using SST transition turbulence model. Durham cascade which is similar to high-pressure axial flow turbine for simulation is used. The aim of fencing in blade passage is to get the maximum benefit from flow deviation and destroying the passage vortex in terms of loss reduction. It is observed that, for the present analysis, fence in the blade passage helps reducing the strength of horseshoe vortex and is capable of restraining the flow along the blade passage. Fence in the blade passage helps in reducing the under turning by 70 in comparison with base case. Fence on end-wall is effective in preventing the movement of pressure side leg of horseshoe vortex and helps in breaking the passage vortex. Computations are carried for different fence height whose curvature is different from the blade camber. The optimum fence geometry and location reduces the loss coefficient by 15.6% in comparison with base case.Keywords: boundary layer fence, horseshoe vortex, linear cascade, passage vortex, secondary flow
Procedia PDF Downloads 3452819 Cold Tomato Paste as an Alternative Therapy for Elderly Clients with Exacerbation of Arthritis
Authors: Mary Therese G. Caluna, Mark Justin B. Campanero, Erlin Maris T. Cantiller, Claudine Mae A. Cantillo, Nerissa L. Caño
Abstract:
Objective: The study determined the effectiveness of cold tomato paste in relieving pain caused by exacerbation of arthritis in the elderly, specifically on clients 60 years old and above. The study focused on alternative, cost-effective and non-pharmacological techniques in relieving pain experienced by the older people with osteoarthritis and rheumatoid arthritis. Methods: Using purposive non-probability sampling, the researchers gathered a total number of 40 subjects that passed the inclusion criteria provided by the researchers. The subjects were divided into two groups, experimental group (20 subjects) and control groups (20 subjects). The Numeric Rating 11-point Scale (NRS-11) was utilized to assess the pain level of the subject prior the application of the treatment and after the application of the treatment. Key findings: There is a significant difference in the pain levels of the experimental group before and after the application of cold tomato paste. This indicates that that the application of cold tomato paste alleviates the pain experienced by elderly clients with exacerbation of arthritis. Conclusion: The effectiveness of cold tomato paste in relieving pain experienced by elderly clients who are in exacerbation of arthritis was proven to be evidence-based. The cold tomato paste application has significant impact in the field of nursing and therefore, can be used in both clinical trials and practices. The effectiveness of cold tomato application promotes innovation in the field of nursing, thus encouraging further researches regarding other uses of tomato and other herbal interventions to relieve the pain caused by osteoarthritis and rheumatoid arthritis.Keywords: alternative therapy, arthritis, cold tomato paste, elderly clients, exacerbation
Procedia PDF Downloads 4182818 The Clinical and Survival Differences between Primary B-Cell and T/NK-Cell Non-Hodgkin Lymphomas in the Nasopharynx, Nasal Cavity, and Nasal Sinus: A Population-Based Study of 3839 Cases in the Seer Database
Authors: Jiajia Peng, Danni Cheng, Jianqing Qiu, Yufang Rao, Minzi Mao, Ke Qiu, Junhong Li, Fei Chen, Feng Liu, Jun Liu, Xiaosong Mu, Wenxin Yu, Wei Zhang, Wei Xu, Yu Zhao, Jianjun Ren
Abstract:
Background: Currently, primary B-cell non-Hodgkin lymphoma (B-NHL) and T/NK-cell non-Hodgkin lymphoma (NKT-NHL) originated from the nasal cavity (NC), nasopharynx (NP) and nasal sinus (NS) distinguished unclearly in the clinic. Objective: We sought to compare the clinical and survival differences of B-NHL and NKT-NHL that occurred in NC, NP, and NS, respectively. Methods: Retrospective data of patients diagnosed with nasal cavity lymphoma (NCL), nasopharyngeal lymphoma (NPL), and nasal sinus lymphoma (NSL) between 1975 and 2017 from the Surveillance, Epidemiology, and End Results (SEER) database were collected. We identified the B/NKT-NHL patients based on the histological type and performed univariate, multivariate, and Kaplan-Meier analyses to investigate the survival rates. Results: Of the identified 3,101 B-NHL and 738 NKT-NHL patients, those with B-NHL in NP were the majority (43%) and had better cancer-specific survival than those in NC and NS from 2010 to 2017 (5-year-CSS, NC vs. NP vs. NS: 81% vs. 83% vs. 82%). In contrast, most of the NKT-NHL originated from NC (68%) and had the highest CSS rate in the recent seven years (2010-2017, 5-year-CSS: 63%). Additionally, the survival outcomes of patients with NKT-NHL-NP (HR: 1.34, 95% CI: 0.62-2.89, P=0.460) who had received surgery were much worse than those of patients with NKT-NHL-NC (HR: 1.07, 95% CI: 0.75-1.52, P=0.710) and NKT-NHL-NS (HR: 1.11, 95% CI: 0.59-2.07, P=0.740). NKT-NHL-NS patients who had radiation performed (HR: 0.38, 95% CI: 0.19-0.73, P=0.004) showed the highest survival rates, while chemotherapy performed (HR: 1.01, 95% CI: 0.43-2.37, P=0.980) presented opposite results. Conclusions: Although B-NHL and NKT-NHL originating from NC, NP and NS had similar anatomical locations, their clinical characteristics, treatment therapies, and prognoses were different in this study. Our findings may suggest that B-NHL and NKT-NHL in NC, NP, and NS should be treated as different diseases in the clinic.Keywords: nasopharyngeal lymphoma, nasal cavity lymphoma, nasal sinus lymphoma, B-cell non-Hodgkin lymphoma, T/NK-cell non-Hodgkin lymphoma
Procedia PDF Downloads 1742817 Treating On-Demand Bonds as Cash-In-Hand: Analyzing the Use of “Unconscionability” as a Ground for Challenging Claims for Payment under On-Demand Bonds
Authors: Asanga Gunawansa, Shenella Fonseka
Abstract:
On-demand bonds, also known as unconditional bonds, are commonplace in the construction industry as a means of safeguarding the employer from any potential non-performance by a contractor. On-demand bonds may be obtained from commercial banks, and they serve as an undertaking by the issuing bank to honour payment on demand without questioning and/or considering any dispute between the employer and the contractor in relation to the underlying contract. Thus, whether or not a breach had occurred under the underlying contract, which triggers the demand for encashment by the employer, is not a question the bank needs to be concerned with. As a result, an unconditional bond allows the beneficiary to claim the money almost without any condition. Thus, an unconditional bond is as good as cash-in-hand. In the past, establishing fraud on the part of the employer, of which the bank had knowledge, was the only ground on which a bank could dishonour a claim made under an on-demand bond. However, recent jurisprudence in common law countries shows that courts are beginning to consider unconscionable conduct on the part of the employer in claiming under an on-demand bond as a ground that contractors could rely on the prevent the banks from honouring such claims. This has created uncertainty in connection with on-demand bonds and their liquidity. This paper analyzes recent judicial decisions in four common law jurisdictions, namely, England, Singapore, Hong Kong, and Sri Lanka, to identify the scope of using the concept of “unconscionability” as a ground for preventing unreasonable claims for encashment of on-demand bonds. The objective of this paper is to argue that on-demand bonds have lost their effectiveness as “cash-in-hand” and that this is, in fact, an advantage and not an impediment to international commerce, as the purpose of such bonds should not be to provide for illegal and unconscionable conduct by the beneficiaries.Keywords: fraud, performance guarantees, on-demand bonds, unconscionability
Procedia PDF Downloads 1002816 Development of CaO-based Sorbents Applied to Sorption Enhanced Steam Reforming Processes
Authors: P. Comendador, I. Garcia, S. Orozco, L. Santamaria, M. Amutio, G. Lopez, M. Olazar
Abstract:
In situ CO₂ capture in steam reforming processes has been studied in the last years as an alternative for increasing H₂ yields and H₂ purity in the product stream. For capturing the CO₂ at the reforming conditions, CaO-based sorbents are usually employed due to their properties at high temperature, low cost and high availability. However, the challenge is to develop high-capacity (gCO₂/gsorbent) materials that retain their capacity over cycles of operation. Besides, since the objective is to capture the CO₂ generated in situ, another key aspect is the sorption dynamics, which means that, in order to efficiently use the sorbent, it has to capture the CO₂ at a rate equal to or higher than the generation rate. In this work, different CaO-based materials have been prepared to aim at meeting these criteria. First, and by using the wet mixing method, different inert materials (Mg, Ce and Al) were combined with CaO. Second, and with the inert material selected (Mg), the effect of its concentration in the final material was studied. Transversally, the calcination temperature was also evaluated. It was determined that the wet mixing method is a simple procedure suitable for the preparation of CaO sorbents mixed with inert materials. The materials prepared by mixing the CaO with Mg have shown satisfactory anti-sintering properties and adequate sorption kinetics for their application in steam reforming processes. Regarding the concentration of Mg in the solid, it was concluded that high values contribute to the stability but at the expense of losing sorption capacity. Finally, it was observed that high calcination temperatures negatively affected the sorption properties of the final materials due to the decrease in the pore volume and the specific surface area.Keywords: calcination temperature effect, CO₂ capture, Mg-Ce-Al stabilizers, Mg varying concentration effect, Sorbent stabilization
Procedia PDF Downloads 75